There's no 3G version of the Vita 2000, so they're continuing to sell the 1000 3G model. I believe that the intention is to discontinue the 1000 WiFi model at some point - that'll probably happen quietly, and it's possible the manufacturing of 1000 WiFI models for this market has already ended.

I can sort-of see the logic of splitting out 3DS and 3DS LL sales (quite physically different hardware) but not splitting Vita 1000 and 2000 sales (arguably an updated version of the same hardware), but I do think that combining the 3DS numbers would give a more useful picture.